Party-line telephone system.



No. 774,543. PATENTED NOV. 8, 1904. E. VOLLMER.

PARTY LINE TELEPHONE SYSTEM.

APPLICATION FILED NOV. 20, 1903.

3 SHEETS-SHEET 1.

NO MODEL.

WITNESSES: 6'2 W WM M- A IN VENTOR ,ZZZZnn- VZZZmez' A77'ORNEYS PATENTED NOV. 8, 1904.

F. VOLLMER.

PARTY LINE TELEPHONE SYSTEM.

APPLICATION FILED NOV. 20, 1903.

3 SHEETS-SHEET 2.

vND MODEL.

1 INVENTOI? FeZZan 762271262" WW v 9 WITNESSES:

No.774,543. PATENTED NOV. 8, 904. r

F. VOLLMER.

PARTY LINE TELEPHONE SYSTEM.

APPLICATION FILED NOV. 20. 1903. N0 MODEL. a SHEE TSSHBET a.

as in WITNESSES: IN VENTOH Wi M 23079 7 0727; zez' UNITED STATES Patented November 8, 1904:.

PATENT I ()FFIcE.

FELTON VOLLMER, OF WVINSTED, MINNESOTA.

PARTY-LINE TELEPHONE SYSTEM.

' SPECIFICATION forming part of Letters Patent No. 774,543, 'dated November 8 1904, Application filed November 20,1903. Serial Ni). 181,956. (NomodeL) To all whmn it 7nay'concern:

My invention relates to telephony, my more particular object being to produce a party-line telephone system in which a subscriber at one station may calla subscriber at any station selected without disturbing other stations upon the line and yet silently indicating to all other stations that the line is busy.

My invention further relates to certain improvements in mechanism suitable for partyline telephones and admitting of either of general or special use,as hereinafter described, and pointed out in'the appended claims.

Reference is to be had to the accompanying drawings, forming a part of this specification, in which similar characters of reference indicate corresponding parts in all the figures.

Figure l is a vertical section upon the line 1 1 of Fig. 2, looking in the direction of the arrow, showing an improved casing, together with certain mechanism connected therewith as used in connection with my system. Fig. 2 is a central vertical section upon the line 2 2 of Fig. 1 looking in the direction of the arrow. Fig. 3 is a horizontal section taken upon the line 3 3 of Fig. 1 looking in the direction of the arrow. Fig. L is a detail view showing the cam and contact mechanism actuated thereby for opening and closing the clock-controlled circuit. Fig. 5 is a detail view showing the cam and a part of the electrical connections for selecting a particular station to the exclu 12 of seventy-five ohms resistance. In front of the magnet 10, which is of the bipolar type, is an armature 13, provided with an arm 14, and upon this arm is pivotally mounted a pawl 15, which engages a ratchet-wheel 16, rigidly mounted upon arevoluble shaft 17. A dial-plate 18 is formed within the casing 9 and is covered by a glass plate 19. A revoluble pointer or indicator-hand 20 is free to rotate over the dial-plate 18. A gear-wheel 21, rigidly mounted upon a revolubleshaft ,23, meshes with another gear-wheel 22, rigidly mounted upon the revoluble shaft 17. A cam 26, provided with a comparatively high lobe 27 and with a low or flat lobe 28, is rigidly mounted upon the shaft 23, so as to turn therewith. Upon this cam 26 are curved metallic flanges 29 30, engaging, respectively, the high and the low lobes, said flanges being disposed as indicated in Fig. 5. A post 31 depends from the casing, as shown in Fig. 2, and on said post is pivotally mounted at 47 a lever 32, provided with a pin 33 to be engaged by the flanges 29 on the cam 26. By this means the revolution of the cam 26 in acontra-clockwise direction, as seen from the left of Fig. 1, is such as to cause the flanges 29 30 to raise the lever 32. The cam 26 is insulated from the shaft 23 by means of an insulating-collar 34:. A cam 35, made of metal and mounted on the shaft 23, is provided with apertures .36 37 filled with insulating material, as indicated in Fig. 4:, the insulating material being flush with the faces of the cam. This cam is insulated from the shaft 23 by means of an insulating-collar 38, and integral with said cam are lobes 38 39 of equal height and exactly alike. Mounted over the cam upona post or stem 12 is a lever 40, provided with a pin 4E1, which is engaged by the lobes 38 39 when the cam is rotated. The relative position of the cams 26 and upon the shaft 23 is such that when the pin 33 rests upon the flange 29, as indicated in Fig. 5, the lobe 38 of the cam 35 is slightly to the left of the pin-41, as seen in Fig. 4, so that the lobe 38 does not prevent the lever 40 from dropping freely, provided the lever is not otherwise supported. In other words, there is a certain point of rotation (indicated in Figs. 4: and 5) in which the lever 32 is not free to drop; but l the lever 40 is free to drop unless supported by the hook 52, hereinafter described. A contact member 43 is disposed below the lever 40 and may be engaged at intervals by the same. Somewhat similarly a contact member 44 is disposed below the lever 32 (see Fig. 5) and may be engaged thereby. The levers 32 and 40 are of metal and capable of serving as conductors.

The magnet 12 is provided with an armature 45, mounted upon a swinging hook 46, this hook normally supporting the lever 32, as indicated at both stations in Fig. 7. The magnet 11 is provided with an armature 51, mounted upon aswinging hook 52, which hook normally supports the lever 40, as indicated by dotted lines in Fig. 4.

At each of the stations is a clock 53, provided with a pendulum-rod 54, which is engaged by an oscillating arm 55, this'arm being pivoted at 57 (see Fig. 6) and provided with a swinging contact member 56. As the pendulum-rod 54 swings the contact member 56 engages the contact members 59, which are substantially of a horseshoe shape, as shown in Fig. 6, and are mounted upon a board 58. From one of these contact members 59 a wire 60 leads to the local battery 61, this battery being connected by a wire 62 with a contact-spring 63. (Shown to better advantage in Fig. 4.) This spring continually engages the cam 35, which is of metal, as above explained. A somewhat similar contact-spring 64 is disposed below the spring 63 and is free to engage the cam 35 except when the insulating-bushings 36 37 are in such position as to be engaged by the spring 64, as indicated in Fig. 4. A wire 65 is connected with the magnet 10, as shown in Figs. 7 and 8, and also from said magnet a wire 66 leads to one of the contact members 59, so that contact is continuously made and broken by the oscillation of the contact member 56, which is controlled by the arm 55. A wire 67 connects the wire 62 with the lever 40, indicated in Figs. 4, 7 and 8. A wire 68 connects the contact member 43 (shown in Fig. 4) with the wires 65 and 69. The short wire 69 is connected with the contact-spring 64 and with the wire 65, as shown in Fig. 4.

Each station is provided with a generator 69 an electric hell or similar alarm 70, and with a casing 71, containing the telephone mechanism proper. The mouthpiece is shown at 72 and the receiver at 7 3. A. manually'operated indicator 75 is mounted upon a disk 75, as shown at each station in Figs. 7 and 8. A push-button 76, connected by a wire 74 with the generator 69, is provided with a contact 77 and is connected by a wire 7 8 with a wire 79, this wire 79 being connected with contact members 0 and A, as indicated in Figs. 7 and 8. The contact members 1 2 3 of the dial B are connected by wires 80, 81, and

82 with the respective contacts 1 2 3 of the manually-operated indicator 75, as shown at all of the stations shown in Figs. 7 and 8. The bell connections, however, are slightly different at the different stations. At station No. 1 a wire 83 connects the contact 1 of the indicator B with the bell 70. At station No. 2 a wire 84 connects the contact member 2 with the bell 70, whereas at station No. 3 a wire 85 connects the contact 3 with the bell 70. It will be seen, therefore, that at each station the bell 70 is connected with a separate member 1, 2, or 3 of the automatic inclicator B. This is practically the only difference in construction between the several mechanisms used at the'diiferent stations.

Upon the bell 70 at each station a wire 86 is connected with the magnet 12, and from this magnet a wire 87 is connected with the binding-post 88, this post being in turn connected by a wire 89 with the contact member 90" of a manually-operated switch 90, provided with another contact member 90, these parts being of ordinary construction. From the switch 90 a wire'91 leads to the generator 69. The switch-hook (shown at 92) is pressed upward by a spring 92, but is normally weighted down by the receiver 73. The receiver is connected by wires 94 95 with the binding-post 88 and the transmitter 96, which may be of the magneto type or of any other type desired. From the transmitter a wire 97 leads upward to the switch-hook 92. A contact 98 is engaged by the switch-hook 92 when the same rises, and this contact is in communication with a binding-post 99. This binding-post is connected by a wire 100 with a ground-wire 101, the upper end of which is connected with the movable hand 20.

The contact-button A is connected by a wire 102 with the magnet 11, and a wire 109 connects the magnet 11 with a wire 103, which is in turn connected to the line-wire 104.

As above indicated, the wiring at each station is practically identical with that at the other station, the only difference being in the connection of the bell 70.

The operation of my invention is as follows: Suppose that the several stations upon the line are in their normal condition, the apparatus being at rest, as indicated in Fig. 7. The levers 40 and 32 now rest upon their respective hooks 52 and 46. Suppose that the subscriber at station No. 1 desires to call the subscriber at station No. 2. The subscriber at station No. 1 (see lower part of Figs. 7 and 8) places the manually-controlled index 75 upon the number of the station desired, which, as above indicated, is 2. He then momentarily depresses the push-button 76, thereby causing the same to engage the contact-button 77. WVhile holding the push-button thus closed, he gives the generator 69 a few turns. Two circuits are thus closed, one being a shunt from the other, and they are traced as follows: first,

from the ground at station 1 through the wire 101 to hand on 0, thence through wire 78, push-button 76, wire 74, generator 69, key 90, (now elevated,) wire 89, wire 87, wire 31, lever 32, hook 46 to wire 103, line 104, thence to all of the other stations upon the line, entering the same in parallel 'by means of the several wires 103, magnets 11, wires 102, hand 20, wires101 to the ground; second, the abovementioned shunt-circuit, which leaves wire 103 at station 1, passes upward to wire 109, magnet 11, thence downward through wire 102 to contact-button A, whence it rejoins the main circuit through the Wire 78, the difference. of potential in the shunt-circuit being due to the fact that the two shunt-terminals are so connected with the main circuit that the shunt forms a bridge over the generator 69 in the main circuit. In other words, one terminal of the shunt-circuit is connected with the main circuit at a point between the generator and the ground, whereas the other terminal of the shunt-circuit is connected with the main circuit at a point between the generator and the other stations, so that when the generator sends an impulse through the main circuit above described it necessarily sends an impulse through the shunt-circuit containing the magnet 11 at the calling-station. eral magnets 11 at the several stations attract their several armatures, thereby causing the several hooks 52 to drop the respective levers 40 resting thereupon. These levers, as indi cated in Fig. 4, are only prevented from dropping into horizontal position by the hooks 52,

so that when the magnets 11 are energized the levers 40 instantly become horizontal and engage the several contact members 43 at all of the stations. This movement of the lever 40 at each of the stations completes a local circuit at each station, as follows: battery 61, Fig. 6, wire 60, contact members 56 59, wire 66, magnet 10, wires 68, Fig. 4, contact member 43, lever 40, wires 67 62, back to battery 61-that is to say, at the moments when the clock-pendulum 54 keeps the contact members 56 59 closed the circuit just traced is completed, the lever 40 resting upon the contact 43, as described. The clock-pendulum 54 being in motion, however, the circuit just described is continually broken, as indicated in Fig. 6. Each time this circuit is closed by the pendulum the magnet 10 is energized, attracting its armature 13, thereby causing the lever 14 to oscillate, (see Fig. 2,) the pawl 15 thus being caused to rotate the ratchet-wheel 16. This ratchet-wheel in turn drives the gearing above described and causes the rotation of the shaft 23, carrying the two cams 35 and 26: The rotation of the shaft 23 and its cams continues until three-quarters of a revolution is, made. Referring to Fig. 4, it will be seen that if the cam 35 at each station be given three-quarters of a turn the lobe 39 will be brought into a position directly over the The sevshaft 23 and that'in making this movement it will lift the lever 40 from the position indicated in dotted lines in Fig. 4 to the position indicated in full lines in said figure. It will also be seen that three-quarters of a revo-' lution will bring the insulating material 36 into the position now occupied by the insulating material 37. When this occurs, the circuit is opened, for the reason that the lever 40 no longer engages the contact member 43 and the spring 64 no longer engages the metallic portion of the cam 35. Hence the movements of the clock-pendulum 54 for closing the contact members 56 59 are unable to close the battery-circuit, and thus the rotation of the shaft 23 stops. It follows, therefore, that after the impulse above described is given by the calling-station the two cams at every station upon the line, including the calling-station, are caused to each make three-quarters of a revolution. As soon as the impulse is given and while the cams are in motion the calling subscriber releases his push-button 76, watches the dial B, and as soon as the hand 20 is upon the number of the station desiredto wit, No. 2, in the present instance-he depresses the key 90, so that the same engages the contact-button 90 and again gives the generator 69 a few turns. He thereby completes the following circuit: ground at station No. 1, wire 101, hand 20, contact member 2, wire 81, index 75, Wire 74 wire 74, generator 69, wire 91, key 90, (now depressech) wire 103, wire 83, bell 70, wire 86, magnet 12, wire 87, wire 31, lever 32, (now on its hook 46,) hook 46 to line 103, thereby energizing the magnet 12 of the calling-station, passing out to line 104. The line being thus energized tends, of course, to send a current through such stations as offer a ground for it. It happens, however, that the only station which can do this is station No. 2, for the reason that the wire '84 is not duplicated at the other stations. It is true that each of the other stations has its wire corresponding to the wire 84 at the second station. For instance, station No. 3 has a wire 85 connected with the third contact-button; but this wire 85 is not available for ringing station No. 3 so long as the hand 20 at each of the stations is upon the contact-button No. 2. The circuit therefore proceeds to the ground through station No. 2, as follows: through wire 103, hook 46, lever '32, (now on hook 46,) wire 31, Wire 87, magnet 12, wire 86, bell 70, wire 83, wire 84, con.- tact-button 2, hand 20, (now on contact-button 2,) wire 101 to ground. The bell at station No. 2 is thus rung, and the magnets 12 at this station and at the calling-station only are energized. All this occurs, it will be understood, while the cams are in motion at every station and before the three-quar.- ters turn is completed. Now since the magnet 12 at station No. 2 and the magnet 12 at IIO station No. 1 are the only magnets 12 which are energized at any of the stations it follows that at stations No. 1 and No. 2 only the hook 46 is withdrawn, thereby allowing the lever 32 to drop into its horizontal position, as indicated by dotted lines in Fig. 5 and as shown in Fig. 8. WVhile in that position the lobe cannot act on the pin to raise the lever. At the other stations the magnet 12 not being energized the several levers 32 are not thrown into the horizontal position. On the contrary, they are elevated so as to clear their respective hooks, as indicated in Fig. 5. This is because the lobe 27 is somewhat higher or deeper than the lobe 28. The levers 32 are therefore raised in all of the stations, except the station calling and the one called. hen, therefore, the cams come to a stop after the three-quarters turn, as above described, the mechanism of the calling and called stations will be in the position indicated at stations No. 1 and No. 2 in Fig. 8, whereas at all of the other stations the mechanism will be as indicated at station No. 3 in said figure. The only bells sounded are at the calling and called stations. The subscribers at stations No. 1 and No. 2 now remove their receivers 73, thereby leaving the talking-circuit intact. The three-quarters turn brings the hand 20, which was originally upon the zero-contact, around to the contact A and the followingcircuit through the calling and called stations No. 1 and No. 2 is as follows: ground at station No. 1, wire 100, binding-post 99, con tact member 98, switch-hook 92, (now elevated and engaging contact member 98,) wire 97, transmitter 96, which may be of the magnetic type, wire 95, receiver 73, wire 94:, binding-post 88, wire 87, wire 31, lever 32, (now horizontal,) contact member 14, wire 68, line 10 1 to station No. 2, thence through wire 68, contact member 4 1, lever 32, (now horizontah) wire 31, wire 87, binding-post 88, wire 94, receiver 73, wire 95, transmitter 96, wire 97, switch-hook 92, contact member 98, bindingpost 99, and wire 100 to ground at station No. 2. This talking-circuit is of comparatively low resistance and is not impaired by any waste at any of the other stations. It will be noted that owing to the fact that the lever 32 at all of the other stations is raised out of engagement with its hook 46 and no other subscriber at any other station is enabled to ring or to eavesdrop, for the reason that he is unable to close any circuit whatever upon the line. Moreover, the hand 20 upon his dial shows him that the line is busy. When the conversation is finished, the party callingto Wit, the subscriber at station No. 1turns in an impulse by closing his push-button 76 and giving the generator a few turns, thereby completing the following circuit: ground at station No. 1, wire 101, hand 20, (now resting on contact member A,) wire 79, whence the current divides. The main portion of the current now passes through wire 78, push-but ton 76, generator 69*, key 90, (now elevated,) wire 87, wire 31, lever 32, contact member 14, wire 68 to line, thence at station No. 2 to wire 103, magnet 11, wire 102, hand 20, wire 101 to ground. From the wire 79 at station No. 1, where the current divides, as above stated, a shunt passes upward through wire 102, magnet 11, and wires 109 and 103 to main line 104. The magnet 11, which is of great resistance, (1,000 ohms,) is thus bridged onto the main circuit. These main and shunt circuits energize the magnets 11 at all stations, starting all of the escapements and causing the shaft 23 at each stationto make one quarter of a turn, thereby restoring all of the instruments to the normal position. (Indicated in Fig. 7.) The manner of effecting the onequarter turn rotation of the shaft 23 and the cams is as follows: The magnets 11 at all the stations being energized attract their armatures 51 and release their hooks 52 from the levers 10, thereby causing the same to engage the contact members 13 and again completing the local circuit, as above described. The oscillations of the pendulum now make and break the contact, as above described, and the rotation of the cams 35 begins with the insulation 36 beneath the spring 6 1 and ceases when the spring 64L engages the insulation 37, thereby opening the local or battery circuit, serving as a motor-circuit, the levers 4:0 meanwhile having been raised back upon their respective hooks by the lobes 38, as indicated in Fig. 4. This leaves all instruments upon the line in their normal position.

Having thus described my invention, I claim as new and desire to secure by Letters Patent 1. In a party-line telephone system,the combination of a revoluble shaft at each station, electric mechanism at each station for actuating said shaft at such station, means controllable from another station for stopping and starting said electric mechanism at all of the stations, time-controlled mechanism at each station for governing said electric mechanism, selective telephone mechanism at each station, open-circuit wiring connecting the telephone mechanism of one station with that of the others, and selective mechanism controllable by said revoluble shafts for throwing any one of said telephone mechanisms into circuit and others out of circuit.

2. In a party-line telephone system, the combination of a'plurality of revoluble shafts disposed at different stations, separate magnetic mechanisms for actuating said revoluble shafts, selective mechanism controllable by movements of said shafts for cutting particular stations into and out of circuit, a separate local circuit at each station for energizing the magnetic mechanism at such station, a timecontrolled contact at each station for opening and closing the local circuit at such station,

ITO

circuits from one of said stations to another.

L. In a party-line telephone system, the combination of o pen-circuit wiring extending from one station to another, contact mechanism disposed at the several stations for completing the circuit from one station to another, motor mechanism at each station for actuating said contact mechanism at said stations, time-controlled mechanism at each station for governing said motor mechanism at that station, and means controllable at will from any of the stations for stopping and starting said motor mechanism Without disturbing the continuous action of said time-controlled mechanism.

5. In a party-line telephone system, the combination of a plurality of revoluble shafts disposed at different stations, separate magnetic mechanisms for actuating said revoluble shafts, selective mechanism controllable by movements of said shafts for cutting particular stations into and out of circuit, a separate local circuit at each station for energizing the magnetic mechanism at such station, a contact at each station for opening and closing the 10- cal circuit at such station, a clock at each station for actuating said contact at such station, and means controllable at will from one of the stations for placing said last-mentioned contact under control of said clock and removing the same from said control of said clock, substantially as described.

6. In a party-line telephone system the combination of a revoluble shaft at each station, motor mechanism for actuating said revoluble. shaft, a time-controlled mechanism at each station for governing said motor mechanism at that station, means controllable at will from one of the stations for simultaneously connecting the motor mechanism at other stations with the time-controlled mechanism at said station and for disconnectingthe same, and a contact mechanism at each station controllable by the shaft at that station for cutting any one of said stations into circuit and others of said stations out of circuit.

7. In a party-line telephone system,the combination of a plurality of revoluble shafts, each located at a station, separate motor mechanisms disposed at the several stations for rotating said shafts respectively, a time-com trolled mechanism at each station for governing the motor mechanism at that station, electric mechanism controllable at will from each of the stations for connecting said time-controlled mechanism at other stations with the motor mechanism at said station and for disconnecting the same therefrom, and contact mechanism connected with said shaft and opened and closed thereby for the purpose of completing circuits from one of said stations to another.

8. In a party-line telephone system, the combination of a main circuit extending from station to station, a local circuit at each station, gearing at each station for throwing said local circuit into and out of communication with said main circuit, said gearing being provided with a revoluble cam, contact mechanism having a movable member disposed within the path of said cam and free to be actuated thereby, a second local circuit connected with said contact mechanism and adapted to be temporarily thrown into and out of action by said cam, magnetic mechanism controllable by said main circuit for temporarily closing said last-mentioned local circuit, clockwork disposed at each station and running continuously, and contact mechanism controllable by said clockwork for opening and closing said last-mentioned local circuit when the same is otherwise closed by said contact mechanism.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

FELTON VOLLMER.

I/Vitnesses:

JAs. STIMER, C. R. VOLLMER. 

